Sprawling Angkor Brought Down by Overpopulation, Study Suggests

Cambodia's long-lost temple complex of Angkor is the world's largest known preindustrial settlement, reveals a new radar study that found 74 new temples and more than a thousand manmade ponds at the site. (See a photo gallery of Angkor's newly uncovered sprawl).

But urban sprawl and its associated environmental devastation may have led to the collapse of the kingdom, which includes the renowned temple of Angkor Wat, the study suggests.

Ever since the late 16th century, when Portuguese traders spied the towers of the monument poking through a dense canopy of trees, people have puzzled over the demise of the Angkor civilization.

Now a new archaeological map created using jungle-penetrating radar has revealed traces of vast suburban sprawl surrounding the many temples and the walled central city of Angkor Thom.

Extensive waterworks threaded through the low-density development, channeling the flow of three rivers through agricultural fields, homes, and local temples.

In the end, residents of greater Angkor likely struggled with the ecological consequences of transforming the landscape.

The new survey found breached spillways and canals clogged with silt, suggesting that environmental degradation made the infrastructure increasingly difficult to maintain.

Mystery Civilization

The Khmer kingdom of Angkor rose in the ninth century A.D. and thrived for 600 years before its leaders left to resettle near the modern Cambodian capital of Phnom Penh.

The civilization is renowned to this day for building the massive temple of Angkor Wat—often called the world's largest single religious monument—in the early 12th century.

Although the kings of Angkor etched into stone such significant moments in their history, they left no message during the settlement's decline. That mysterious departure has fueled a smoldering controversy among archaeologists.

Until recently, warfare and changing religion were the prime suspects, according to anthropologist Charles Higham of the University of Otago in Dunedin, New Zealand. Higham's own work has unearthed evidence into the origins of Angkor.